In the UK the British Dragonfly Society maintains a website with details of dragonfly recording in Great Britain, including useful papers on habitat management and creating ponds for dragonflies.
The Digital Dragonflies site has details of how to scan live dragonflies using a flatbed scanner, and some amazing images - look at the dragonfly catalog and damselflies of Texas.
Dutch dragonfly association (Nederlandse Vereniging voor Libellenstudie, NVL) this site is mostly in Dutch and aims to unite amateur and professional researchers. A checklist of the European Dragonfly fauna is provided.
Robert Thompson's photographic website this site has a small selection of excellent images from Robert Thompson's extensive photographic library which includes dragonflies, butterflies, moths, orchids, birds and landscapes.